Mobile terminal and handover method thereof

Abstract

A mobile terminal and a method to transmit a handover complete message in a handover process are provided. The handover method of the present invention includes determining, when a handover command message is received, a handover complete message transmission period, transmitting, when channel establishment information is received, a handover complete message during the handover complete message transmission period, and completing, when a handover complete message transmission period expires, handover to communicate with a base station to which the mobile terminal is handed over. The mobile terminal and handover method thereof are capable of transmitting the handover complete message repeatedly during a predetermined period, resulting in reduction of a probability of a handover failure.

What is claimed is: 
     
       1. A handover method of a mobile terminal, the method comprising:
 determining, when a handover command message is received, a handover complete message transmission period by measuring an environment of the mobile terminal, and 
 determining the handover complete message transmission period according to environment measurements of the mobile terminal, wherein the determining of the handover complete message transmission period comprises comparing the measured environment of the mobile terminal with predetermined environment threshold values; 
 transmitting, when channel establishment information is received, a handover complete message during the handover complete message transmission period; and 
 completing, when a handover complete message transmission period expires, handover to communicate with a base station to which the mobile terminal is handed over. 
 
     
     
       2. The method of  claim 1 , wherein the determining of the handover complete message transmission period comprises:
 starting a timer for counting the handover complete message transmission period; and 
 transmitting a handover request message to the base station. 
 
     
     
       3. The method of  claim 2 , wherein the determining of the handover complete message transmission period further comprises receiving the channel establishment information from the base station. 
     
     
       4. The method of  claim 1 , wherein the environment of the mobile terminal comprises at least one of a received signal level and a received signal quality. 
     
     
       5. The method of  claim 1 , further comprising transmitting, prior to receiving the handover command message, a measurement report message. 
     
     
       6. The method of  claim 5 , wherein the measurement report message comprises at least one of identity information of at least one neighbor cell and a serving cell on which the mobile terminal has camped, and information on signal strengths between the at least one neighbor cell and serving cell and the mobile terminal. 
     
     
       7. A mobile terminal comprising:
 a communication unit for receiving a handover command message from a base station, and 
 for transmitting a handover complete message to the base station; and 
 a control unit for determining, when a handover command message is received, a handover complete message transmission period by measuring an environment of the mobile terminal, and 
 determining the handover complete message transmission period according to environment measurements of the mobile terminal, wherein the control unit compares the measured environment of the mobile terminal with predetermined environment threshold values, for controlling the communication unit to transmit, when channel establishment information is received, the handover complete message during the handover complete message transmission period, and 
 for completing when a handover complete message transmission period expires, handover to communicate with a base station to which the mobile terminal is handed over. 
 
     
     
       8. The mobile terminal of  claim 7 , wherein the control unit starts a timer for counting the handover complete message transmission period and controls the communication unit to transmit a handover request message to the base station. 
     
     
       9. The mobile terminal of  claim 8 , wherein the communication unit receives the channel establishment information from the base station. 
     
     
       10. The mobile terminal of  claim 7 , wherein the environment of the mobile terminal comprises at least one of a received signal level and a received signal quality. 
     
     
       11. The mobile terminal of  claim 7 , wherein the control unit controls the communication unit to transmit, prior to receiving the handover command message, a measurement report message. 
     
     
       12. The mobile terminal of  claim 11 , wherein the measurement report message comprises at least one of identity information of at least one neighbor cell and a serving cell on which the mobile terminal has camped, and information on signal strengths between the at least one neighbor cell and serving cell and the mobile terminal.